Certainly, but I think that would be wasteful.
The guy that used to be the US distributor owned a winery. When the vines started to bud up, he would spray the vines, leading to rachis elongation, allowing better grape growth and easier penetration of fungicides.
However, generally speaking, orchids are not particularly good at foliar uptake, thanks to the waxy cuticle layers on their leaves - an adaptation intended to slow water loss, it also slows uptake. I’m not saying that would be ineffective, just less so than for a terrestrial plant, plus…mature phals and catts seem to have thick cutices, while young plants and thin-leaved species don’t, so should absorb it better.